1. Field of the Invention
The present invention relates generally to message filtering. More particularly, this invention relates to email filtering using latent semantic analysis.
2. Copyright Notice/Permission
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawings hereto: Copyright© 2000, Apple Computer, Inc., All Rights Reserved.
3. Background
As the use of computers and the Internet have proliferated, so too has the use of email. Many businesses and consumers use email as a prominent means of communication. Not surprisingly, the exponential growth of the medium has also attracted the interest of commercial email advertisers. Commercial email advertisers obtain email addresses from a variety of sources, for example, from email vendors, or from commercial web sites, often without the permission of the owners of the email addresses. The email addresses may then be used to promote the products and services of the commercial email advertisers, or of the parties they represent.
The result is a deluge of unsolicited email received by hapless email users. One method to deal with unsolicited email is for a user to manually select and delete the unsolicited email. Other methods provide for recognizing a message sent in bulk to multiple recipients, and to either discard or tag the message as a possible unsolicited message. Still other methods maintain a database of addresses of known senders of unsolicited email and on receipt of the email, automatically discard those received from the known senders of unsolicited email. Still other methods use key-word filters. This method provides for scanning the subject and/or the body of the email message for some pre-determined keywords, and if detected, the message may be either discarded or tagged as suspicious.
Despite the methods described above, commercial email advertisers use ingenious methods to frustrate the efforts of email recipients. For example, to defeat the detection of bulk email, the email messages may be routed through a maze of servers so that ultimately, the message does not appear to be a bulk emailing. To defeat the system that tracks the address of known senders of unsolicited messages, the originating address of the unsolicited email may be changed often. To confuse keyword filter methods, the subject field of the email may be deceitfully titled, for example, “In response to your query”. Moreover, the key-word filtering method suffers from other significant problems, for example, when trying to filter out email messages from pornographic email advertisers using the word “sex”, legitimate anatomical or biological articles that include the word “sex” may also be eliminated.